The feasibility of using less than optimally prepared tissues for electron microscopic study has been adequately demonstrated. Use of such materials permits not only retrospective studies to be carried out on accumulated human material but also permits the examination of rarities. Combining the techniques of transmission electron microscopy and scanning electron microscopy with current techniques of light microscopy (including the use of one to two micron thick plastic embedded sections) permits further study of a number of disease entities many of which can only be adequately studied in human tissue. Studies are ongoing as well in a number of disease entities in human tissues both optimally an suboptimally prepared for electron microscopic examination. Although there is some emphasis on the study of a variety of corneal disease (e.g., band keratopathy, Meesmann's epithelial dystrophy, Reis-Bucklers' dystrophy, etc.) a number of other problems in ophthalmic pathology are being examined. Occasionally, a suitable animal model for a human disease becomes available for study and one such model is currently under investigation.